Retrospective diagnosis of two rabies cases in humans by high throughput sequencing

• Two cases of rabies among humans were detected using a broad-range PCR analysis followed by high throughput sequencing.
• Diagnoses were subsequently confirmed using a fluorescent antibody test, an enzyme-linked immunosorbent assay (ELISA) and a mouse inoculation test.
• Two strains of rabies virus were isolated and characterized.

BackgroundRabies is prevalent in 150 countries and is definitely found in Russian Federation. The average registered incidence of rabies infection among animals in Russia is 3000 cases per year. At least 500,000 cases of animal bites and scratches are registered in the Russia every year, but only 2–4 cases of rabies infection in humans are reported per year. This relatively low incidence of rabies infection among humans is the result of a well-organized program of rabies surveillance and control as well as the readily available vaccination and immunoglobulin therapies. However, physician awareness of rabies infection in patients with acute encephalopathy is low, and some cases of rabies remain undiagnosed.ObjectivesA retrospective study of autopsy materials from patients who died of encephalitis of unknown etiology in the Astrakhan region of Russia in 2003.Study designA broad-range polymerase chain reaction (PCR) analysis followed by high throughput sequencing were used for the diagnosis.ResultsTwo cases of rabies were detected and subsequently confirmed using a fluorescent antibody test, an enzyme-linked immunosorbent assay (ELISA) and a mouse inoculation test. Two strains of rabies virus were isolated and characterized using virological methods. The entire genome of each strain was sequenced.